Like grep -v for a string over 2 lines? Sed?

Hi,

I have a log file that I need to monitor as it's being written to, and I want to exclude certain strings from the output. At the moment I'm using ...

 tail -f LogFileName_`date +%d`.log | egrep -v "First String To Exclude | 2nd string | 3rd string" 

...which works OK - but now I need to exclude another specific string and it's a string that is split over two lines.

Could anyone tell me how to do this please?

Thanks very much.

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Edit to add ....

I'm sorry. I guess I should have posted this in "UNIX for Dummies".

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Jake

1) Might be easier to understand if we can see the file and what you are trying to select (not select) for.
2) grep (or egrep) can use a file. When you get start to have several options, put them all in a file (say called exclude) one to a line, then do your

egrep -vf exclude initial_file

Just a suggestion, as it may make your coding easier to read and maintain.